Фізико-хімічні особливості отримання жароміцних ніобієвих сплавів системи Nb-Ti-Al- Cr-Mo методами плавки та порошкової металургії

• Date: 2025
• Main Authors: Марич, М.В., Бродніковський, М.П., Баглюк, Г.А., Кузнєцова, Т.Л.
• Format: Article
• Language: Ukrainian
• Published: Physico-technological Institute of Metals and Alloys 2025
• Subjects: жароміцні сплави ніобію; дугова плавка в аргоні; порошкова металургія; гаряче штампування; відпал; вакуумне спікання; структура; жароміцність
• Online Access: https://www.metalsandcasting.com/index.php/mcu/article/view/307
• Journal Title: Metal and Casting of Ukraine

Niobium alloys of the Nb-Ti-Al system are one of the most promising alloys in the rocket and space industry, especially alloys with a low specific gravity (≤ 7g/cm3), which have a yield strength at 1000 °C of not less than 500 MPa. Our studies have established the possibility of creating promising cast heat-resistant alloys of this system, and a promising heat-resistant alloy 57Nb-10Cr-5Al-21Ti-7Mo (at. %), which meets the specified requirements, was also developed. However, the large crystallization interval of cast alloys of this system, the thermophysical features of their crystallization cause the possibility of the formation of dendritic structures, the development of dendritic liquation and segregation, and the tendency to the formation of crystallization cracks, which reduces the operational characteristics of cast alloys. In this regard, there was a need to investigate the possibilities of obtaining these alloys by the powder metallurgy method. The article presents the results of a study of the influence of the production technology and the main technological parameters on the structural features and mechanical properties of the promising heat-resistant alloy 57Nb-10Cr-5Al-21Ti-7Mo (%, at.), obtained by the melting method and by two promising powder metallurgy technological schemes. The possibility of obtaining a homogeneous fine-crystalline alloy 57Nb-10Cr-5Al-21Ti-7Mo (at. %) with strength equal to that of the cast alloy by the powder metallurgy method using both open hot forging of billets from a mixture of powders at a temperature of 1200 °C with annealing at 1600 °C in vacuum (the first technological scheme), and the second vacuum-technological scheme – after sintering at 1600 °C of billets from a mixture of powders and thermoplastic compression deformation in vacuum has been established. The use of hot thermomechanical processing of sintered blanks at relatively low temperatures (1200 °C) in the range of solid-phase reactions provides materials with high dispersion of the structure and a high degree of homogeneity. The possibility of creating a composite material, the regularities of its dissolution during the annealing process, which allow controlling the processes of porosity formation and grain sizes of the alloy (57Nb-21Ti-5Al-10Cr-7Mo) at. % when obtained by the powder metallurgy method, is shown.